Vibrational energies of monodeuterated dimethyl ether based on high level ab initio potential energy surfaces

Torsion and COC bending vibrational energies for monodeuterated dimethyl ether are reported. A total number of 78 torsion-bending sublevels below 700 cm−1 have been obtained using a three dimensional Hamiltonian at a CCSD(T)/aug-cc-VTZ level of theory. Guided by the results obtained for other dimethyl ether isotopologues, the Hamiltonian parameters have been readjusted to obtain a spectrum that is expected to lie closer to future experimental results. In addition to this, a torsional-torsional two dimensional potential has been derived projecting the three dimensional potential energy surface and the torsional barrier height and level splitting magnitudes have also been reckoned.